This invention relates to the manufacture and structure of a radio frequency antenna, and, more particularly, to such an antenna fabricated from plastic elements.
An antenna radiates or receives energy. A radio frequency (RF) antenna for use in a microwave radar radiates or receives energy in the radio frequency range that is typically 1-20 GHz (gigahertz), but may be higher or lower. The RF antenna may be structured to radiate or receive energy over a broad bandwidth or a narrow bandwidth. RF antennas are widely used in military applications such as aircraft and missile guidance.
A number of designs of RF antennas are known. Many are based upon microwave waveguide principles, in which a waveguide directs energy in a selected direction and radiates the energy outwardly into free space (or equivalently, receives energy radiated through free space).
The principal known techniques for fabricating RF antennas include foil forming, dip brazing, and electroforming of metallic-based structures. Individual antenna elements are fastened to the feed structure by mechanical fasteners, adhesives, or solders. Mechanical fasteners are time-consuming to install. Adhesives typically require careful application and curing at elevated temperature for an extended period of time. Solders are sometimes difficult to use, especially when there is an attempt to achieve precision alignment of soldered structures. Additionally, all of these techniques result in a relatively heavy antenna structure, which is undesirable in a flight-worthy vehicle.
There is a need for an improved approach to the design and fabrication of RF antennas that reduces both cost and weight of the antenna, and is compatible with either broad band or narrow band applications. The present invention fulfills this need, and further provides related advantages.